DOCSLIB.ORG

West Vs East Antarctica

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
West Vs East Antarctica West versus East Antarctica The Antarctic continent is made up of two distinct geographic regions, separated by one of the largest mountain ranges on Earth, the Transantarctic Mountains (TAM). This impressive mountain chain cuts across Antarctica, being over 3500 km in length, 100-200 km wide and reaching heights of 4500 m. By aligning a map of Antarctica so the Greenwich Meridian (zero longitude) is at the top, these very different regions on either side of the TAM, can be compared. West Antarctica forms the hook to the left, East Antarctica forms the rest of the continent. Practical Task Introduction Convection is the movement of a liquid or gas, due to West Antarctica East Antarctica differences in it's density. Temperature differences cause density differences. • much younger • extremely ancient geological history geologically history What to do 1. Stir a teaspoon of Miso • rocks are mainly less • oldest known Antarctic soup paste into a glass than 500 million years rocks at 4000 million or cup of hot water old. years old 2. Allow to stand and • a large part is below sea • mainly above sea level watch for convection level currents. • composed of islands, • composed of a large archipelagos and small mass of ancient rock How it works land masses Within the glass the movement is caused by the hotter • connected by the West • covered by the thick parts of the Miso soup being less dense and rising, Antarctic Ice Sheet East Antarctic ice sheet likewise the colder liquid tends to sink. Since heat is lost (WAIS) (EAIS) from the outer surfaces a central column of rising soup is formed. Even small temperature differences are sufficient • WAIS sits on land that is • EAIS flows outwards to keep this process occurring. mostly below sea level over ancient bedrock Note that it is not the actual temperature of the soup which drives the convection current but rather differences • mountainous and • mainly flat except for the in soup temperature, which explains why the current spectacular throughout buried Gamburtsev continues as the soup cools. Mountains Convection currents like this occur in all hot liquids (and gases) but are made more visible here because of the soy paste within the soup. The Transantarctic Mountains The uplift of the Transantarctic Mountains was caused Relevance by the same process which split Gondwana apart. After • Convection currents in the Earths mantle contribute to Gondwana disintegrated, Antarctica continued to be the movement of continents (e.g.Antarctica). stretched (rifted) and pulled apart. This stretching caused • Convection currents in the ocean caused by East and west Antarctica to drift apart and the differences in water temperature (and salinity) drive Transantarctic Mountains to be uplifted on the edge of the ocean currents. These currents control Earths food rift. chains, weather and climate. As the surface stretched some crustal blocks sank, creating large scale features which remain to this day, namely: • the steep eastern faces of the Transantarctic Adapted from material by Bryan Storey, University of Mountains. Canterbury by Donald Reid, iMatters.co.nz in association • the large areas of West Antarctic that lie below sea with Gateway Antarctica, University of Canterbury. level. Curricula: Science L4 - 8, Social Studies L3 - 4, Geography L6 - 8. Images: Donald Reid, Alexrk2, Wikicommons For a full range of Antarctic and Southern Ocean resources visit: The Antarctic Hub www.antarctichub.org.
Load more

Recommended publications
  • Postspreading Rifting in the Adare Basin, Antarctica: Regional Tectonic Consequences
    Article Volume 11, Number 8 4 August 2010 Q08005, doi:10.1029/2010GC003105 ISSN: 1525‐2027 Postspreading rifting in the Adare Basin, Antarctica: Regional tectonic consequences R. Granot Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA Now at Institut de Physique du Globe de Paris, 4 Place Jussieu, F‐75005 Paris, France ([email protected]) S. C. Cande Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA J. M. Stock Seismological Laboratory, California Institute of Technology, 1200 East California Boulevard, 252‐21, Pasadena, California 91125, USA F. J. Davey Institute of Geological and Nuclear Sciences, PO Box 30368, Lower Hutt, New Zealand R. W. Clayton Seismological Laboratory, California Institute of Technology, 1200 East California Boulevard, 252‐21, Pasadena, California 91125, USA [1] Extension during the middle Cenozoic (43–26 Ma) in the north end of the West Antarctic rift system (WARS) is well constrained by seafloor magnetic anomalies formed at the extinct Adare spreading axis. Kinematic solutions for this time interval suggest a southward decrease in relative motion between East and West Antarctica. Here we present multichannel seismic reflection and seafloor mapping data acquired within and near the Adare Basin on a recent geophysical cruise. We have traced the ANTOSTRAT seismic stratigraphic framework from the northwest Ross Sea into the Adare Basin, verified and tied to DSDP drill sites 273 and 274. Our results reveal three distinct periods of tectonic activity. An early localized deforma- tional event took place close to the cessation of seafloor spreading in the Adare Basin (∼24 Ma).
    [Show full text]
  • Ice Shelf Advance and Retreat Rates Along the Coast of Queen Maud Land, Antarctica K
    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 106, NO. C4, PAGES 7097–7106, APRIL 15, 2001 Ice shelf advance and retreat rates along the coast of Queen Maud Land, Antarctica K. T. Kim,1 K. C. Jezek,2 and H. G. Sohn3 Byrd Polar Research Center, The Ohio State University, Columbus, Ohio Abstract. We mapped ice shelf margins along the Queen Maud Land coast, Antarctica, in a study of ice shelf margin variability over time. Our objective was to determine the behavior of ice shelves at similar latitudes but different longitudes relative to ice shelves that are dramatically retreating along the Antarctic Peninsula, possibly in response to changing global climate. We measured coastline positions from 1963 satellite reconnaissance photography and 1997 RADARSAT synthetic aperture radar image data for comparison with coastlines inferred by other researchers who used Landsat data from the mid-1970s. We show that these ice shelves lost ϳ6.8% of their total area between 1963 and 1997. Most of the areal reduction occurred between 1963 and the mid-1970s. Since then, ice margin positions have stabilized or even readvanced. We conclude that these ice shelves are in a near-equilibrium state with the coastal environment. 1. Introduction summer 0Њ isotherm [Tolstikov, 1966, p. 76; King and Turner, 1997, p. 141]. Following Mercer’s hypothesis, we might expect Ice shelves are vast slabs of glacier ice floating on the coastal these ice shelves to be relatively stable at the present time. ocean surrounding Antarctica. They are a continuation of the Following the approach of other investigators [Rott et al., ice sheet and form, in part, as glacier ice flowing from the 1996; Ferrigno et al., 1998; Skvarca et al., 1999], we compare the interior ice sheet spreads across the ocean surface and away position of ice shelf margins and grounding lines derived from from the coast.
    [Show full text]
  • Rapid Cenozoic Glaciation of Antarctica Induced by Declining
    letters to nature 17. Huang, Y. et al. Logic gates and computation from assembled nanowire building blocks. Science 294, Early Cretaceous6, yet is thought to have remained mostly ice-free, 1313–1317 (2001). 18. Chen, C.-L. Elements of Optoelectronics and Fiber Optics (Irwin, Chicago, 1996). vegetated, and with mean annual temperatures well above freezing 4,7 19. Wang, J., Gudiksen, M. S., Duan, X., Cui, Y. & Lieber, C. M. Highly polarized photoluminescence and until the Eocene/Oligocene boundary . Evidence for cooling and polarization sensitive photodetectors from single indium phosphide nanowires. Science 293, the sudden growth of an East Antarctic Ice Sheet (EAIS) comes 1455–1457 (2001). from marine records (refs 1–3), in which the gradual cooling from 20. Bagnall, D. M., Ullrich, B., Sakai, H. & Segawa, Y. Micro-cavity lasing of optically excited CdS thin films at room temperature. J. Cryst. Growth. 214/215, 1015–1018 (2000). the presumably ice-free warmth of the Early Tertiary to the cold 21. Bagnell, D. M., Ullrich, B., Qiu, X. G., Segawa, Y. & Sakai, H. Microcavity lasing of optically excited ‘icehouse’ of the Late Cenozoic is punctuated by a sudden .1.0‰ cadmium sulphide thin films at room temperature. Opt. Lett. 24, 1278–1280 (1999). rise in benthic d18O values at ,34 million years (Myr). More direct 22. Huang, Y., Duan, X., Cui, Y. & Lieber, C. M. GaN nanowire nanodevices. Nano Lett. 2, 101–104 (2002). evidence of cooling and glaciation near the Eocene/Oligocene 8 23. Gudiksen, G. S., Lauhon, L. J., Wang, J., Smith, D. & Lieber, C. M. Growth of nanowire superlattice boundary is provided by drilling on the East Antarctic margin , structures for nanoscale photonics and electronics.
    [Show full text]
  • The Evolution of the Antarctic Ice Sheet at the Eocene-Oligocene Transition
    Geophysical Research Abstracts Vol. 19, EGU2017-8151, 2017 EGU General Assembly 2017 © Author(s) 2017. CC Attribution 3.0 License. The evolution of the Antarctic ice sheet at the Eocene-Oligocene Transition. Jean-Baptiste Ladant (1), Yannick Donnadieu (1,2), and Christophe Dumas (1) (1) LSCE, CNRS-CEA, Paris, France ([email protected]), (2) CEREGE, CNRS, Aix-en-Provence, France An increasing number of studies suggest that the Middle to Late Eocene has witnessed the waxing and waning of relatively small ephemeral ice sheets. These alternating episodes culminated in the Eocene-Oligocene transition (34 – 33.5 Ma) during which a sudden and massive glaciation occurred over Antarctica. Data studies have demonstrated that this glacial event is constituted of two 50 kyr-long steps, the first of modest (10 – 30 m of equivalent sea level) and the second of major (50 – 90 m esl) glacial amplitude, and separated by ∼ 200 kyrs. Since a decade, modeling studies have put forward the primary role of CO2 in the initiation of this glaciation, in doing so marginalizing the original “gateway hypothesis”. Here, we investigate the impacts of CO2 and orbital parameters on the evolution of the ice sheet during the 500 kyrs of the EO transition using a tri-dimensional interpolation method. The latter allows precise orbital variations, CO2 evolution and ice sheet feedbacks (including the albedo) to be accounted for. Our results show that orbital variations are instrumental in initiating the first step of the EO glaciation but that the primary driver of the major second step is the atmospheric pCO2 crossing a modelled glacial threshold of ∼ 900 ppm.
    [Show full text]
  • Sea Level and Climate Introduction
    Sea Level and Climate Introduction Global sea level and the Earth’s climate are closely linked. The Earth’s climate has warmed about 1°C (1.8°F) during the last 100 years. As the climate has warmed following the end of a recent cold period known as the “Little Ice Age” in the 19th century, sea level has been rising about 1 to 2 millimeters per year due to the reduction in volume of ice caps, ice fields, and mountain glaciers in addition to the thermal expansion of ocean water. If present trends continue, including an increase in global temperatures caused by increased greenhouse-gas emissions, many of the world’s mountain glaciers will disap- pear. For example, at the current rate of melting, most glaciers will be gone from Glacier National Park, Montana, by the middle of the next century (fig. 1). In Iceland, about 11 percent of the island is covered by glaciers (mostly ice caps). If warm- ing continues, Iceland’s glaciers will decrease by 40 percent by 2100 and virtually disappear by 2200. Most of the current global land ice mass is located in the Antarctic and Greenland ice sheets (table 1). Complete melt- ing of these ice sheets could lead to a sea-level rise of about 80 meters, whereas melting of all other glaciers could lead to a Figure 1. Grinnell Glacier in Glacier National Park, Montana; sea-level rise of only one-half meter. photograph by Carl H. Key, USGS, in 1981. The glacier has been retreating rapidly since the early 1900’s.
    [Show full text]
  • A Review of Ice-Sheet Dynamics in the Pine Island Glacier Basin, West Antarctica: Hypotheses of Instability Vs
    Pine Island Glacier Review 5 July 1999 N:\PIGars-13.wp6 A review of ice-sheet dynamics in the Pine Island Glacier basin, West Antarctica: hypotheses of instability vs. observations of change. David G. Vaughan, Hugh F. J. Corr, Andrew M. Smith, Adrian Jenkins British Antarctic Survey, Natural Environment Research Council Charles R. Bentley, Mark D. Stenoien University of Wisconsin Stanley S. Jacobs Lamont-Doherty Earth Observatory of Columbia University Thomas B. Kellogg University of Maine Eric Rignot Jet Propulsion Laboratories, National Aeronautical and Space Administration Baerbel K. Lucchitta U.S. Geological Survey 1 Pine Island Glacier Review 5 July 1999 N:\PIGars-13.wp6 Abstract The Pine Island Glacier ice-drainage basin has often been cited as the part of the West Antarctic ice sheet most prone to substantial retreat on human time-scales. Here we review the literature and present new analyses showing that this ice-drainage basin is glaciologically unusual, in particular; due to high precipitation rates near the coast Pine Island Glacier basin has the second highest balance flux of any extant ice stream or glacier; tributary ice streams flow at intermediate velocities through the interior of the basin and have no clear onset regions; the tributaries coalesce to form Pine Island Glacier which has characteristics of outlet glaciers (e.g. high driving stress) and of ice streams (e.g. shear margins bordering slow-moving ice); the glacier flows across a complex grounding zone into an ice shelf coming into contact with warm Circumpolar Deep Water which fuels the highest basal melt-rates yet measured beneath an ice shelf; the ice front position may have retreated within the past few millennia but during the last few decades it appears to have shifted around a mean position.
    [Show full text]
  • Mount Harding, Grove Mountains, East Antarctica
    MEASURE 2 - ANNEX Management Plan for Antarctic Specially Protected Area No 168 MOUNT HARDING, GROVE MOUNTAINS, EAST ANTARCTICA 1. Introduction The Grove Mountains (72o20’-73o10’S, 73o50’-75o40’E) are located approximately 400km inland (south) of the Larsemann Hills in Princess Elizabeth Land, East Antarctica, on the eastern bank of the Lambert Rift(Map A). Mount Harding (72°512 -72°572 S, 74°532 -75°122 E) is the largest mount around Grove Mountains region, and located in the core area of the Grove Mountains that presents a ridge-valley physiognomies consisting of nunataks, trending NNE-SSW and is 200m above the surface of blue ice (Map B). The primary reason for designation of the Area as an Antarctic Specially Protected Area is to protect the unique geomorphological features of the area for scientific research on the evolutionary history of East Antarctic Ice Sheet (EAIS), while widening the category in the Antarctic protected areas system. Research on the evolutionary history of EAIS plays an important role in reconstructing the past climatic evolution in global scale. Up to now, a key constraint on the understanding of the EAIS behaviour remains the lack of direct evidence of ice sheet surface levels for constraining ice sheet models during known glacial maxima and minima in the post-14 Ma period. The remains of the fluctuation of ice sheet surface preserved around Mount Harding, will most probably provide the precious direct evidences for reconstructing the EAIS behaviour. There are glacial erosion and wind-erosion physiognomies which are rare in nature and extremely vulnerable, such as the ice-core pyramid, the ventifact, etc.
    [Show full text]
  • GSA TODAY • Southeastern Section Meeting, P
    Vol. 5, No. 1 January 1995 INSIDE • 1995 GeoVentures, p. 4 • Environmental Education, p. 9 GSA TODAY • Southeastern Section Meeting, p. 15 A Publication of the Geological Society of America • North-Central–South-Central Section Meeting, p. 18 Stability or Instability of Antarctic Ice Sheets During Warm Climates of the Pliocene? James P. Kennett Marine Science Institute and Department of Geological Sciences, University of California Santa Barbara, CA 93106 David A. Hodell Department of Geology, University of Florida, Gainesville, FL 32611 ABSTRACT to the south from warmer, less nutrient- rich Subantarctic surface water. Up- During the Pliocene between welling of deep water in the circum- ~5 and 3 Ma, polar ice sheets were Antarctic links the mean chemical restricted to Antarctica, and climate composition of ocean deep water with was at times significantly warmer the atmosphere through gas exchange than now. Debate on whether the (Toggweiler and Sarmiento, 1985). Antarctic ice sheets and climate sys- The evolution of the Antarctic cryo- tem withstood this warmth with sphere-ocean system has profoundly relatively little change (stability influenced global climate, sea-level his- hypothesis) or whether much of the tory, Earth’s heat budget, atmospheric ice sheet disappeared (deglaciation composition and circulation, thermo- hypothesis) is ongoing. Paleoclimatic haline circulation, and the develop- data from high-latitude deep-sea sed- ment of Antarctic biota. iments strongly support the stability Given current concern about possi- hypothesis. Oxygen isotopic data ble global greenhouse warming, under- indicate that average sea-surface standing the history of the Antarctic temperatures in the Southern Ocean ocean-cryosphere system is important could not have increased by more for assessing future response of the Figure 1.
    [Show full text]
  • Antarctic Primer
    Antarctic Primer By Nigel Sitwell, Tom Ritchie & Gary Miller By Nigel Sitwell, Tom Ritchie & Gary Miller Designed by: Olivia Young, Aurora Expeditions October 2018 Cover image © I.Tortosa Morgan Suite 12, Level 2 35 Buckingham Street Surry Hills, Sydney NSW 2010, Australia To anyone who goes to the Antarctic, there is a tremendous appeal, an unparalleled combination of grandeur, beauty, vastness, loneliness, and malevolence —all of which sound terribly melodramatic — but which truly convey the actual feeling of Antarctica. Where else in the world are all of these descriptions really true? —Captain T.L.M. Sunter, ‘The Antarctic Century Newsletter ANTARCTIC PRIMER 2018 | 3 CONTENTS I. CONSERVING ANTARCTICA Guidance for Visitors to the Antarctic Antarctica’s Historic Heritage South Georgia Biosecurity II. THE PHYSICAL ENVIRONMENT Antarctica The Southern Ocean The Continent Climate Atmospheric Phenomena The Ozone Hole Climate Change Sea Ice The Antarctic Ice Cap Icebergs A Short Glossary of Ice Terms III. THE BIOLOGICAL ENVIRONMENT Life in Antarctica Adapting to the Cold The Kingdom of Krill IV. THE WILDLIFE Antarctic Squids Antarctic Fishes Antarctic Birds Antarctic Seals Antarctic Whales 4 AURORA EXPEDITIONS | Pioneering expedition travel to the heart of nature. CONTENTS V. EXPLORERS AND SCIENTISTS The Exploration of Antarctica The Antarctic Treaty VI. PLACES YOU MAY VISIT South Shetland Islands Antarctic Peninsula Weddell Sea South Orkney Islands South Georgia The Falkland Islands South Sandwich Islands The Historic Ross Sea Sector Commonwealth Bay VII. FURTHER READING VIII. WILDLIFE CHECKLISTS ANTARCTIC PRIMER 2018 | 5 Adélie penguins in the Antarctic Peninsula I. CONSERVING ANTARCTICA Antarctica is the largest wilderness area on earth, a place that must be preserved in its present, virtually pristine state.
    [Show full text]
  • The Antarctic Contribution to Holocene Global Sea Level Rise
    The Antarctic contribution to Holocene global sea level rise Olafur Ing6lfsson & Christian Hjort The Holocene glacial and climatic development in Antarctica differed considerably from that in the Northern Hemisphere. Initial deglaciation of inner shelf and adjacent land areas in Antarctica dates back to between 10-8 Kya, when most Northern Hemisphere ice sheets had already disappeared or diminished considerably. The continued deglaciation of currently ice-free land in Antarctica occurred gradually between ca. 8-5 Kya. A large southern portion of the marine-based Ross Ice Sheet disintegrated during this late deglaciation phase. Some currently ice-free areas were deglaciated as late as 3 Kya. Between 8-5 Kya, global glacio-eustatically driven sea level rose by 10-17 m, with 4-8 m of this increase occurring after 7 Kya. Since the Northern Hemisphere ice sheets had practically disappeared by 8-7 Kya, we suggest that Antarctic deglaciation caused a considerable part of the global sea level rise between 8-7 Kya, and most of it between 7-5 Kya. The global mid-Holocene sea level high stand, broadly dated to between 84Kya, and the Littorina-Tapes transgressions in Scandinavia and simultaneous transgressions recorded from sites e.g. in Svalbard and Greenland, dated to 7-5 Kya, probably reflect input of meltwater from the Antarctic deglaciation. 0. Ingcilfsson, Gotlienburg Universiw, Earth Sciences Centre. Box 460, SE-405 30 Goteborg, Sweden; C. Hjort, Dept. of Quaternary Geology, Lund University, Sdvegatan 13, SE-223 62 Lund, Sweden. Introduction dated to 20-17 Kya (thousands of years before present) in the western Ross Sea area (Stuiver et al.
    [Show full text]
  • Open-File Report 2007-1047, Extended Abstracts
    U.S. Geological Survey Open-File Report 2007-1047 Antarctica: A Keystone in a Changing World—Online Proceedings for the 10th International Symposium on Antarctic Earth Sciences Santa Barbara, California, U.S.A.—August 26 to September 1, 2007 Edited by Alan Cooper, Carol Raymond, and the 10th ISAES Editorial Team 2007 Extended Abstracts Extended Abstract 001 http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea001.pdf Ross Aged Ductile Shearing in the Granitic Rocks of the Wilson Terrane, Deep Freeze Range area, north Victoria Land (Antarctica) by Federico Rossetti, Gianluca Vignaroli, Fabrizio Balsamo, and Thomas Theye Extended Abstract 002 http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea002.pdf Postcollisional Magmatism of the Ross Orogeny (Victoria Land, Antarctica): a Granite- Lamprophyre Genetic Link S. Rocchi, G. Di Vincenzo, C. Ghezzo, and I. Nardini Extended Abstract 003 http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea003.pdf Age of Boron- and Phosphorus-Rich Paragneisses and Associated Orthogneisses, Larsemann Hills: New Constraints from SHRIMP U-Pb Zircon Geochronology by C. J. Carson, E.S. Grew, S.D. Boger, C.M. Fanning and A.G. Christy Extended Abstract 004 http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea004.pdf Terrane Correlation between Antarctica, Mozambique and Sri Lanka: Comparisons of Geochronology, Lithology, Structure And Metamorphism G.H. Grantham, P.H. Macey, B.A. Ingram, M.P. Roberts, R.A. Armstrong, T. Hokada, K. by Shiraishi, A. Bisnath, and V. Manhica Extended Abstract 005 http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea005.pdf New Approaches and Progress in the Use of Polar Marine Diatoms in Reconstructing Sea Ice Distribution by A.
    [Show full text]
  • Download (Pdf, 236
    Science in the Snow Appendix 1 SCAR Members Full members (31) (Associate Membership) Full Membership Argentina 3 February 1958 Australia 3 February 1958 Belgium 3 February 1958 Chile 3 February 1958 France 3 February 1958 Japan 3 February 1958 New Zealand 3 February 1958 Norway 3 February 1958 Russia (assumed representation of USSR) 3 February 1958 South Africa 3 February 1958 United Kingdom 3 February 1958 United States of America 3 February 1958 Germany (formerly DDR and BRD individually) 22 May 1978 Poland 22 May 1978 India 1 October 1984 Brazil 1 October 1984 China 23 June 1986 Sweden (24 March 1987) 12 September 1988 Italy (19 May 1987) 12 September 1988 Uruguay (29 July 1987) 12 September 1988 Spain (15 January 1987) 23 July 1990 The Netherlands (20 May 1987) 23 July 1990 Korea, Republic of (18 December 1987) 23 July 1990 Finland (1 July 1988) 23 July 1990 Ecuador (12 September 1988) 15 June 1992 Canada (5 September 1994) 27 July 1998 Peru (14 April 1987) 22 July 2002 Switzerland (16 June 1987) 4 October 2004 Bulgaria (5 March 1995) 17 July 2006 Ukraine (5 September 1994) 17 July 2006 Malaysia (4 October 2004) 14 July 2008 Associate Members (12) Pakistan 15 June 1992 Denmark 17 July 2006 Portugal 17 July 2006 Romania 14 July 2008 261 Appendices Monaco 9 August 2010 Venezuela 23 July 2012 Czech Republic 1 September 2014 Iran 1 September 2014 Austria 29 August 2016 Colombia (rejoined) 29 August 2016 Thailand 29 August 2016 Turkey 29 August 2016 Former Associate Members (2) Colombia 23 July 1990 withdrew 3 July 1995 Estonia 15 June
    [Show full text]